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In this work, Au/Fe3O4 nanocomposite materials with exact spinel structure were successfully synthesized where impurities-free Fe3O4 was prepared using sol-gel autocombustion method and gold was doped with various concentrations 1, 3, and 5 wt.% using conventional deposition–precipitation method. Methylene blue with fixed concentration (0.05 mM) was used to investigate the photocatalytic activity under visible light. Due to homogeneous and controlled compositions, Au/Fe3O4 nanocomposites showed enhanced photocatalytic efficiency than pure Fe3O4. [ABSTRACT FROM AUTHOR]

Transient liquid phase (TLP) bonding process was applied to join magnesium alloy AZ31 samples with minimum microstructural changes. The magnesium samples were coated by 5 μm nickel prior to the TLP bonding. Bonding conditions of 8 MPa uniaxial pressure and 520 °C bonding temperature were applied for all bonds at various bonding times. The microstructure across the joint regions was examined as a function of bonding time (5–60 min). Investigating the change in Ni contents was examined by EDS line scan. It was noticed that Ni coating could not be observed by SEM for bonds made at 30 and 60 min due to complete dissolution of the Ni coating. Second phase particles containing Mg 2 Ni intermetallics were observed by X-ray Photoelectron Spectroscopy (XPS) near the joint region. The shear strength of the bonds initially increases with the increase in bonding time till 20 min. On the other hand, with bonding times over 20 min the shear strength decreases. Therefore the optimum bonding time at the conditions applied was concluded to be 20 min. [ABSTRACT FROM AUTHOR]

Abstract: TLP diffusion bonding of two dissimilar aerospace alloys, Ti–6Al–4V and Al7075, was carried out at 500°C using 22μm thick Cu interlayers for various bonding times. Joint formation was attributed to the solid-state diffusion of Cu into the Ti alloy and Al7075 alloy followed by eutectic formation and isothermal solidification along the Cu/Al7075 interface. Examination of the joint region using SEM, EDS and XPS showed the formation of eutectic phases such as, Ө(Al2Cu), T(Al2Mg3Zn3) and Al13Fe along grain boundaries within the Al7075 matrix. At the Cu/Ti alloy bond interface a solid-state bond formed resulting in a Cu3Ti2 phase formation along this interface. The joint region homogenized with increasing bonding time and gave the highest bond strength of 19.5MPa after a bonding time of 30min. [Copyright &y& Elsevier]

Abstract ZnO:Mn nanoparticles with different Mn concentrations (0, 1 and 3 at%) have been produced by sol-gel wet chemical route. The effect of manganese doping on the structural, micro-structural, optical and photocatalytic properties of zinc oxide nanoparticles (ZnO NPs) has been investigated. X-ray diffraction and Raman investigations confirmed high quality monophase wurtzite hexagonal structure of pure and Mn-doped ZnO NPs; and no separate phase of dopant has been found. The chemical composition of Mn-doped ZnO NPs has been confirmed by X-ray photoelectron spectroscopic measurements. Additionally, the presence of Mn 2p3/2 peak at 640 eV in XPS spectra confirmed the addition of Mn in ZnO host matrix. TEM micrograph showed spherical shaped NPs with an average size in the range of 21–35 nm. The high resolution TEM images exhibit the highly crystalline nature and the inter-planar distances of hexagonal wurtzite ZnO:Mn nanoparticles. Raman study also confirmed the hexagonal wurtzite structure of ZnO:Mn (0, 1 and 3 at%) NPs. Optical absorption spectra showed a red shift in the absorbance band edge with increasing Mn doping in ZnO. The increasing doping level of Mn in ZnO resulted in the narrowing of bandgap and the increasing of visible light absorption. For photocatalytic behavior, the methylene blue (MB) decolorization efficiency in the very presence of synthesized pure and Mn-doped ZnO NPs has been studied under visible light irradiation. Photoluminescence measurements showed that the band edges of ultraviolet and green emissions are slightly red shifted; and PL intensity decreases with the increasing concentration of Mn in ZnO NPs. The significantly enhanced photocatalytic activity of Mn doped ZnO NPs is because of the increase in light absorption and the effective separation between photogenerated electron-hole pairs. [ABSTRACT FROM AUTHOR]

Modulating the thermal conductivity has been a pragmatic approach for the development of high-performance thermoelectric material and thereby a step forward towards commercialization. Despite some efforts, the reduction in thermal conductivity of SrTiO 3 ceramic has not been fully realized. In this work, Ti 3 AlC 2 in 3, and 7 vol% were uniformly incorporated in SrTiO 3 through nanostructured powder processing. The pristine SrTiO 3 and composites powders were consolidated by the spark plasma sintering at 1200 °C under uniaxial pressure of 50 MPa. Thermal properties of the bulk samples were evaluated from room temperature to 750 K through laser flash analysis. The thermal conductivity of SrTiO 3 based composites decreases substantially with the addition of nanostructured Ti 3 AlC 2 from the pristine SrTiO 3 bulk sample. The reduction in thermal conductivity of 7 vol% composites is more than 30% at room temperature and even higher at elevated temperatures from the SrTiO 3. The interface thermal resistance was estimated which indicates a dominant role in diminishing the thermal conductivities of the composites. The results suggest that the addition of Ti 3 AlC 2 as a second phase and nanostructuring through ball milling has significantly altered the phonon scattering mechanisms through multiple factors and thereby contributed to reducing effective thermal conductivities of the composites. This, work provide a scalable and economical route for the development of high-performance thermoelectric material. [ABSTRACT FROM AUTHOR]

[Display omitted] • A femtosecond (fs) laser micromachining approach was used in our study. • Optimized parameters achieved highly accurate microtubule texturing of Ti substrates. • Vertically-aligned microtubules along the smooth surface of titanium were fabricated. • Human periodontal fibroblasts were able to attach and migrate into the microtubules. Peri-implantitis leads to the destruction of hard and soft tissues, ultimately leading to a loss of the dental implant supporting structures. Current treatments can limit disease progression; however, true regeneration, characterised by perpendicularly oriented fibre attachment to the implant surface, remains challenging. Herein, we aim to enhance the quality of the peri -implant soft-tissue integration via the fabrication of vertically aligned micropores on Ti alloy (Ti6Al4V, Ti64) implant surfaces. The micropores are created via the subtraction fabrication method known as femtosecond (FS) laser micromachining. This study achieved highly accurate micropore texturing on Ti64 substrates with optimised parameters of 2 × 104 pulses per spot, 100 kHz and 220 FS laser pulse duration. The surface characteristics of human gingival fibroblasts (hGF), such as morphology and roughness, were investigated by scanning electron microscope and optical profiler techniques. The FS micromachining approach resulted in outstanding topographical properties of highly systematic vertically aligned micropores (7 and 15 µm) on the Ti64 surfaces. The response of hGF cells with the micro-patterned surfaces was also investigated by confocal laser scanning microscopy and scanning electron microscopy after ten days in vitro culture. The hGF cells migrated deep (>10 µm) and attached along the internal walls of the vertically orientated micropores demonstrating excellent integration. This pilot study provides a possible new concept for a clinically valuable strategy to enhance Ti surface properties with precise micropores for promoting superior peri -implant subgingival soft tissue integration. [ABSTRACT FROM AUTHOR]

• The undoped and Fe-doped TiO 2 nanoparticles were synthesized by sol-gel route. • The Fe-doped TiO 2 nanoparticles exhibited high photocatalytic activity. • A method for evaluating the electrochemical performance is proposed. • Room temperature paramagnetic behaviour was observed. • The reduction of band gap from 3.31 eV to 3.10 eV was obtained. In this work, undoped and iron doped titania nanoparticles (Fe:TiO 2 NPs) were successfully prepared by sol-gel route with two different Fe concentration (5 and 10 mol.%). The effects of Fe doping into TiO 2 were thoroughly investigated by XRD, TEM, HRTEM, XPS, FTIR, Raman, UV–Visible spectroscopy and VSM. The obtained nanoparticles have narrow size distribution 41–49 nm and were recognized as anatase TiO 2 structure with no signature of Fe cluster or iron oxides as analyzed by X-ray diffraction and Raman. The optical band gap of undoped and iron doped TiO 2 NPs is red shifted with respect to the incorporation of iron content. Room temperature M-H loops revealed that all the samples showed a significant paramagnetic behaviour. The enhanced photocatalytic performance was observed for iron doped titania nanoparticles compared with pure TiO 2 NPs in respect of methylene blue dye degradation in aqueous suspension under visible light illumination. [ABSTRACT FROM AUTHOR]

In the present work, we have investigated the structural, optical, photocatalytic activity, electrical transport and magnetic properties of Fe 3 O 4 nanoparticles and its composite with reduced graphene oxide (Fe 3 O 4 /RGO) by varying the ratio of reduced graphene oxide (RGO: 2% and 4%). Fe 3 O 4 nanoparticles and RGO were synthesized by the modified sol-gel and Hummers methods respectively. The as-prepared samples were examined by various analytical techniques to investigate their functional properties and possible applications. Rietveld refinement analysis of the XRD data reveals face-centered cubic (fcc) structure of the Fe 3 O 4 nanoparticles and confirms the characteristic planes of magnetite phase. The average crystallite size of the Fe 3 O 4 , Fe 3 O 4 /RGO (2%) and Fe 3 O 4 /RGO (4%) samples was estimated using Scherrer's equation and found to be ∼10, 15 and 19 nm respectively. TEM/HRTEM micrographs establish spherical shapes of the magnetite nanoparticles with an average diameter of ∼12 nm for Fe 3 O 4 , while 17 and 20 nm in the nanocomposites respectively. The low temperature resistivity measurements exhibit semiconducting nature of all the samples and follow variable range hopping (VRH) mechanism. The magnetic measurements demonstrate typical superparamagnetic behavior of the samples at room temperature. The photocatalytic performance of the samples has been investigated for the decolorization of methylene blue (MB) organic dye under visible light irradiation. The Fe 3 O 4 /RGO nanocomposites display better adsorption behaviour and excellent photocatalytic activity than RGO and Fe 3 O 4 nanoparticles. This may be due to strong interactions between Fe 3 O 4 nanoparticles and graphene sheets. [ABSTRACT FROM AUTHOR]

The effect of laponite® clay dispersion on the electrical, structural, optical, thermal, and photovoltaic properties of [poly (ethylene oxide)-succinonitrile]-LiI-I 2 solid polymer electrolytes is reported for the first time. The nanoclay belongs to the family of smectite clay minerals and offers a high surface-to-volume ratio, charged surface, galleries, and ionic species. The dispersion has increased the room-temperature electrical conductivity to ~0.5 mS cm−1 for the optimum conducting electrolyte (OCE; x = 2.5%) without altering the pseudo-activation energy. The change is explained using the percolation model utilizing the formation of a space-charge region by the clay. Fourier-transform infrared spectroscopy reveals the greater interaction between clay and succinonitrile than clay and poly (ethylene oxide) and the formation of amorphous domains for the OCE. X-ray diffractometry study shows a shift toward the lower angle for the amorphous hump of the OCE. The OCE exhibits a ~123% increase in short-circuit current density, ~28% decrease in open-circuit voltage, and 29–64% decrease in charge-transfer and Warburg resistances, inferring the active role of the clay in improving the Li+ ion intercalation into and/or adsorption onto the TiO 2. This has resulted in 54% increase in cell efficiency (~3.7% at solar irradiance of 100 mW cm−2). Laponite nanoclay dispersed [poly (ethylene oxide)-succinonitrile]-LiI-I 2 solid polymer electrolyte. Image 1 • The laponite dispersion (x = 2.5%; OCE) increased the σ 25°C value to ~0.5 mS cm−1. • The nanoclay offered high surface area, charged surface, galleries, and Li+ ions. • The clay-succinonitrile interaction was higher than the clay-PEO interaction. • A large increase in current density was responsible for the efficiency improvement. • The EIS study showed a decrease in the charge-transfer and Warburg resistances. [ABSTRACT FROM AUTHOR]